In many medical procedures, a catheter is inserted into the arterial system of a patient, and guided to a target location inside the body, this procedure being generally done under fluoroscopic guidance using a C-arm type of fluoroscopic apparatus. Periodically, the operating physician takes an X-ray snapshot to see where the tip of the catheter is located or, in the event of difficult manipulations, these are performed by the physician under constant fluoroscopic imaging.
Since blood vessels are essentially not visible on an X-ray image, contrast agent (CA) injected through the catheter whenever the operating physician needs to observe the position of the catheter with respect to the blood vessels. However, contrast agent is typically toxic, and the total amount of contrast agent that can be safely delivered to a patient is usually limited. It is herein recognized that a procedure that can reduce the amount of contrast agent is generally beneficial for the patient, because less contrast agent means less stress and fewer possible side effects on the patient and it decreases the risk of having to abort an intervention unsuccessfully because a limit of CA uptake has been reached.
In accordance with an aspect of the invention, a method for providing a virtual contrast agent for blood vessels in a body portion, comprising the steps of: acquiring data for a 3D model from an imaging process; segmenting the data to provide a segmented 3D model of the blood vessels; obtaining a first procedure image of the body portion utilizing a radiation source and an image detector, the procedure image including the blood vessels with contrast agent injection; registering the segmented 3D model with the procedure image, and deriving therefrom parameters relating the positions of the body portion, the radiation source, the image detector, and the 3D model; obtaining a second procedure image of the body portion utilizing the radiation source and the image detector, the second procedure image being obtained without contrast agent injection; and rendering the 3D model and overlaying the 3D model onto the second procedure image. The procedure image is the image used during the intervention procedure.
In accordance with another aspect of the invention, a method for providing a virtual contrast agent includes the step of acquiring data for a 3D model from an imaging process, wherein the imaging process comprises one of magnetic resonance imaging, computerized tomography (CT), and 3D angio, and the procedure images comprises one of magnetic resonance imaging, computerized tomography (CT), 3D angio, fluoroscopy, and ultrasound imaging.
In accordance with still another aspect of the invention, a method for providing a virtual contrast agent for blood vessels in a body portion, comprising the steps of: acquiring data for a 3D model from an imaging process; segmenting the data to provide a segmented 3D model of the blood vessels; obtaining a first procedure image of the body portion utilizing a radiation source and an image detector, the first procedure image including the blood vessels with contrast agent injection; registering the segmented 3D model with the procedure image, and deriving therefrom parameters relating the positions of the body portion, the radiation source, the image detector, and the 3D model by comparing the first procedure image with a number of precalculated projections of the 3D model; obtaining a second procedure image of the body portion utilizing the radiation source and the image detector, the second procedure image being obtained without contrast agent injection; and rendering the 3D model by finding a catheter tip in the second procedure image by rendering a subset of the segmented 3D model including the catheter tip and downstream blood vessel portions; and overlaying the 3D model onto the second procedure image utilizing virtual contrast.
In accordance with still another aspect of the invention, a method for providing a virtual contrast agent for blood vessels in a body portion for angioscopy comprises deriving data from a 3D model using, any of magnetic resonance imaging, computerized tomography (CT), and 3D angio; segmenting the data to provide a segmented 3D model of the blood vessels; generating a first procedure image with a contrast agent present; registering the 3D model with the first procedural image and thereby obtaining xe2x80x9cvirtual camera parametersxe2x80x9d; rendering the 3D model; and overlaying the rendered 3D model onto a second procedure image without contrast, whereby a virtual contrast is achieved.
An object of the present invention is to reduce the amount of contrast agent during an intervention using a catheter inside the arterial tree.